The Fortas Chamber Music Concerts season was supposed to end on Tuesday night with a virtuoso soloist and a well-known string quartet playing a quintet by a neglected figure of the American avant-garde. Instead, it ended with a virtuoso soloist and a well-known string quartet playing Mozart and Brahms. I would guess that at least some in the audience thought this was a change in the right direction.

Pianist Marc-Andre Hamelin, who was supposed to perform with the Pacifica Quartet at the Kennedy Center Terrace Theater, had to pull out of the program at the 11th hour because of a back injury. It was a shame, since the Pacifica has been touring with him and this program and is recording Leo Ornstein’s “Quintette,” the abovementioned avant-garde piece, with him for a future album.

But as substitutions go, this one was pretty stellar, since the Pacifica conveniently had another collaborator nearby. Anthony McGill, the clarinetist, gave a solo recital outside Baltimore on Sunday, and his new CD with the Pacifica, of clarinet quintets by Mozart and Brahms, is coming out Tuesday. So, rather than adapting at the last minute to a soloist whom its members did not know well, the Pacifica was able to slip into a different groove and do a little CD promotion instead.

McGill is the focus of considerable attention at the moment, since after10 years as principal clarinet of the Metropolitan Opera Orchestra, he has just been named to the same position at the New York Philharmonic. (Washingtonians heard him as part of the ill-fated, prerecorded quartet at President Obama’s first inauguration.) High expectations seemed to roll right off his back; McGill has one of those light-hearted stage presences that keep a sense of delight alive in the music. The rejiggered program was able to include the two works from the upcoming CD, and he played them gorgeously, melding with the strings and playing off them and seeming to intensify their richness in his own tones.

There was, however, perhaps a touch too much complacency in the performance as a whole. The Pacifica is an adroit group best known for ambitious, large-scale projects: recording, for instance, the complete quartets of Elliott Carter. They were perfectly fine, but not electrifying, in this bread-and-butter repertoire; first violinist Simin Ganatra offered some impressive fiddling in the Brahms, and violist Masumi Per Rostad sounded smooth and urbane.

Anthony McGill, new clarinetist of the New York Philharmonic, stepped in for pianist Marc-Andre Hamelin in a Pacifica Quartet concert. (David W Finlayson)

The quartet seemed to wake up in Shostakovich’s 7th quartet, which opened with electrical flickers of notes from one instrument to another, and continued in this intensely communicative vein, with Brandon Vamos’s cello growling at Per Rostad’s viola, with a kind of urgency that had been missing in the Mozart.